CA2016554A1 - Method and apparatus for laser cutting repetitive patterns in a continuously moving stream of material - Google Patents
Method and apparatus for laser cutting repetitive patterns in a continuously moving stream of materialInfo
- Publication number
- CA2016554A1 CA2016554A1 CA 2016554 CA2016554A CA2016554A1 CA 2016554 A1 CA2016554 A1 CA 2016554A1 CA 2016554 CA2016554 CA 2016554 CA 2016554 A CA2016554 A CA 2016554A CA 2016554 A1 CA2016554 A1 CA 2016554A1
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- accordance
- conveyor
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- Laser Beam Processing (AREA)
Abstract
Abstract of the Disclosure An apparatus and process for repetitively laser cutting a pattern in a continuously moving stream of material. The material is continuously advanced through a cutting zone where a beam of coherent radiation focused on the material is repetitively shifted along a sequential set of lines in timed relation to the movement of the material. The set of lines define a shape whose geometry represents the area between the desired patterns being cut from the material.
Description
PATENT
Attorniey Docket No 5243-4 ~T~OD ~N~ APPAR~U~ FOR hA8ER CUT~IN~
REPETITIVE PATTBRN8 IN A CONTIN~OU~LY
NOVING 8TREAM OF MATERIA~
Bac~round o~ th~ Invention I. ~iald o~ th Inv~itio~-The present inventlon relatos generally to a method and apparatus for using a laser to cut patterns repetitively in a oontinuous}y moving sheet o~ material.
The known method of laser cutting patterns in a itream o~ ma~erial i8 to sequentially advance the material by a conveyor into a cutting zone, and then while the material is stationary, U9Q an x-y aptical positioner to cut a pattern ~rom the material by moVing a ~ocused beam o~ coherent radiation over the materlal. The beam 1s caused to ~raverse the patt~rn under control of a digital :
:: : :
computer and numeric machine controller which process ~tored data representing the pattern to be cut~ After the pattern is cut, the conveyor starts up to advance cut parts out of, and fresh material into, the cutting zone. Significantly gr~ater throughput can be achieved by laser cutting the patterns if ~he material never stops moving while the cutting takes place.
The present invention is directed to laser cutting patterns in a continuously moving sheet of material. The method of cutting may be characterized as cutting patterns in a moving reference frame. The method and apparatus of the present invention achieves significantly higher throughputs than conventional ~top-to-cutn laser pattern cutting machines because no extra time is needed to move cut parts out of the cutting zone and bring in fre~h material. Also cutting time is reduced by moving the focused laser beam along the conveyor axis in6tead o~ relying only on conveyor movement.
The presen~ invention has particular utility in cutting pa~terns o~ ~abric for mass produced apparel. The advantage-~ of using a laser to cut patterns in fabrio for garments include '~
.
. ~ . : ~ , . . ~
enhanced cutting accuracy, numerical control of the cutting process, little waste, ease of change over to different sizes or patterns and the ability to cut all of the patterns for a single garment out of the same section of cloth. The laser cutting apparatus, however, can efficiently cut only a limited number of layers at a time whereas other pattern cutting devices, such as mechanical cutters, can cut a large number o~ layers to enable increased throughput. This may make them economically competitive with laser cutters when unit production, repeatability and unbundling are not critical. By providing the ability to continuously move material, the present invention enhances the capability of laser cutters to compete with conventional cu~ters by providing increased throughput.
Although the present invention is exemplified by laser cutting patterns in fabric for clothing, it is not so limited. The present invention i6 applicable to cutting patterns in many types o~ continuously moving material where the cutter, such as a focused beam of coherent radiation, can be directed to traverse a repeatable set of cut lines.
;
.: . . . ~ : . . . . .
~ . ~
The present invention is also directed to a device ~or removing material from the conveyor~
When the present laser cutter i6 used to cut cloth, the resultant patterns are highly flexible and difficult to physically manipulate. The present invention provides a device ~or easily and conveniently removing material from the conveyor surface.
II. De3criptio~ o~ th~ Prior Ar~
U.S. Patent No. 3,761,675 for a Material Cutting and Printing System isæued September 25, 1973 to Hughes Aircraft Co. discloses a method and apparatus for cutting material, especially ~abric, using a focused beam of coherent radiation. An x-y positioner under the control of a digital computer scans the beam to cut a pattern in the material.
The computer al60 controls the lasers on-off se~uence. The material is stationary while the pattern is cut.
Laser cutters of the type disclosed in U.S. Patent No. 3,761,675 have been sold by General Systems Research, Inc. o~ Edmonton, Alberta, Canada. These laser cutters use computer programs to generate patterns and control the laser, x-y : . .. . ,~ :,, . . . ~
optical positioner and conveyor. Throughput has been enhanced by using dual laser beams and two or more seguential cutting zones. The conveyor tops while the material is being cut by the laser.
U.S. Patent Nos. 3,811~554 and 3,828,697 for Working Surface for Radiant ~nergy Beam Cutter issued ~ay 21, 1974 and August 13, 1974, respectively, and U.S. Patent No. 3,828,159 issued August 6, 1974 for Laser Cutting Surface disclose honeycomb conveyor slats or ~urfaces which have been used in the prior laser cutters dascribed above.
U.S. Patant No. 3,832,948 for Radiation Method for Making a Surface in Relief issued September 3, 1974 discloses a method and apparatus for making printing plates and other products with an embossed surface by ~canning a beam of csherent radiation over the surface. The on-off sequence for the laser beam is controlled by a dig~tal computer. The printing plate is stationary while its surface is embossed by the cohexent radiation.
,i ., . i . , " . . . . . . ~ ... .. ... .
III. Bum~ar~ o~ the Inve~tion In accordance with the invention, a pattern is repetitively cut by coherent radiation incident on a continuously moving stream of material. A conveyor continuously advances the material through a cutting æone where an electronically controlled x-y positioner traverses ths pot where the coherent radiation is incident on the material through a repetitive set of cut lines. These cut lines, which ultimately define the 6hape of the desired patterns, provide an effici~nt way o~ cutting the pattern in a moving reference frame; that i~, in a continuously moving stream of material~ The terms ~continuous stream"
and ~continuous sheet~ are used interchangeably throughout this description of the invention to mearl material of inde~inite length.
A problem with cutting moving material is that there is a possibility that the positioner will try to ~ollow the material out of the cut zone 1~ the conveyor is moving too rapidly or too 810wly. The problem o~ the positioner drifting out o~ the cut zone is eliminated, in accordance with ~he present invention, synchronizing the sequence o~ cut lines with the conveyor speed so that the positioner returns the beam o~ coherent radiation to the same incident ~pot within the cut zone where it began. To accomplish this result the beam is directed to traverse a repeatable set of lines defining a geometric 6hape, herein called a s~mmetry unit, where the final spot is the starting spot for the next repetition. And the conveyor is controlled to advance the material so that these two points occur at the same location within the cut zone.
Starting and stopping at the Bame spot has a furthsr advantage. The number of pattern repetitions that are going to be cut is entirely variable. Whether it is 5, 15 or 5,000, the Btrategy used to define a symmetry unit must be the ~ame. Starting and stopping the set o~ cut lines at the same spot allows the positioner to cut as many repetitions as desired without drifting out of the cut zone.
Since, in accordance with t~e present lnvention, the conveyor and material move continuously thro~gh the cutting zone, the x-y positioner must compensate for the moving condition ot the conveyor and maintain the same relative veloai~y over the material regardless of the ,~ .. ..
. . : . . . ,, i,,; :~ ; , . , , :
: : ~ : .
direction of motion. Even though the conveyor is moving, the positioner is capable o~ automatically adjusting its ~peed to accommodate the motion and keep the cutting velocity constant with respect to the material. ~hus the control ystem of the present invention i synchronized to the conveyor's movement.
As described in more detail hereinafter, the laser cutter uses a ~equential set of cut lines defining a symmetry unit whose geometric shape represents the space between patterns. This symmetry unit enhances cutting efficiency while also obviating problems inherent to the process of cutting in a moving referenced frame. Because the conveyor is constantly moving while the cutting is taking place there i~ a fini~e amount of time ~o cut each individual line o~ the pattern. To be cut a line must be pre~ent in the cutting zone. Also, a line must be cut before it leaves the cukting zone. The 6ymmetry unit compensates for this problem by minimizing the total length of cut lines and optlmizing their cutting sequence while innuring that oaoh line c~n be cut while it is .
: ' ~ . :
present in the cut zone. The ~ymmetry unit also permits unlimited selection of the number of repeated patterns to be cut.
The set of cut 1 ines within the 6ymmetry unit traver~ed by the incident ~pot of radiation defines the pattern cut in the material. The cut lines selected for the symmetry unit, and their sequenc~, therefore af~ects the capabilities o~ the laser cuttPr. By reducinq the ~otal cut length of a symmetry uni~, the ~ime required to cut a pattern is also reduced, and the cutting process is made more ef~icient assuming a constant cutting velocity. Likewise, efficiency is enhanced by properly ordering the sequence o~ cut lines within a symmetry unit. Also common cut lines need be traversed only once. Thu~ the present invention uses the sy~metry unit to provide a more e~ficient way of cutting a pattern or pattarns in a moving sheet of material.
The symmetry unit of the present invention represents the space between two or more patterns. More particularly, the symmetry unit of the present invention represent~ the minimum number of lines which when cu~ repetitively will produce the desired pattern in the fastest time. Since ,,: :, . - : ,~ ,, ~ -patterns are to be r~petitively cutl and ~ince they are almost always irregular in shape, there is always a certain amount of material between the patterns. ~ather than cut the pattern the x-y positioner causes the coherent radiation to cut the spaces between patterns to create the desired pattern. The result is the ~ame as traversing the pattern itself but the efficiency o~ the cutting process is enhanced. One reason for enhan~ed efficiency is that the perimeter of the space between the patt~rns is less than the perimeter o~
the patterns themselves. By cutting symmetry units it is not necessary to cut out a complete pattern.
Instead the cut lines of a symmetry unit can finish a previous pattern and 6tart the next pattern, which is completed by the next repetition of the symmetry unit. Another way a symmetry unit enhances effi~iency is by minimization o~
~dryhaulN. Dryhaul is when the laser beam has to be turned off to move the beam to a new part of the pattern. Since the cu~ line~ in a 6ymme~ry unit are closQr together than those of a pattern, dryhaul is minimized.
The present invention also provides a device for ef~ectively removing material from the laser cutter's conveyor.
The convsyor surface itself must be specially constructed for use with coherent radiation. Generally, it must be constructed 80 as to support the material for accurate cutting and yet not to be damaged by the radiation. Prior support surfaces have used pins. Hon~ycomb surfaces have also been used to provide a cutting bed. See U.S. Patent Nos. 3,811,554 and 3,828,159.
These ~urfaces, however, do not provide for ready removal of flexible materials such as cloth.
The present invention uses a conveyor ~urface which i8 both suitable ~or use with coherent radiation and cooperates with an apparatus for ~acilitating the removal of the material.
Specifically, the conveyor sur~ace is defined by spaced longitudinally aligned ribs which are suitable for use as a outting ~ed for the in~rared coherent radiation used by the laser cutter. The ribs cooperate with an extractor plate which includes a comb-like edge in inter-spatial engagement with the conveyor ribs. T~e extractor plate pre~erably engages the conveyor at an upward angle to the horizontal so that the pattern pieces slide onto the extractor plats. The pieces are drawn over the extractor plate by a conveyor positioned over its surface. ~his conveyor draws the pattern pieces onto and over the extractor plate.
~r~f De~¢riptlon o~ the Drawing3 For the purpose of illustrating the invention, there is shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.
Fig. 1 is a side elevational view o~ the laser cutter of the present inventionO
FigO 2 is a top plan view of the laser cutter except the laser is not shownO
Fig. 2A is an enlarged plan view of the extractor plate.
Fig. 3 i~ an end view of the laser cutter.
Fig. 4 is an enlarged sectional view of the x-rail and drive motor taken ~rom the aircled portion in Fig. 3.
- . - ~. . . . . . -Fig. 5 is an enlarged partial view of the x-y positioner.
Fig. S i~ a signal ~low diagram for the laser cutter.
Fig. 7 illustrat~s a sleeve pattern as presented on a video monitor.
: Fig. 8 illustrates the relationship between nested, repetitive sleeve patterns.
Fig. 9 illustrates repetitive sleeve patterns as they would appear on an video m~nitor for creation of a ~ym~etry unit.
Fig. 10 illustrates the cut lines for an exemplary symmetry unit.
Fig. 11 illustrates the co~mon lines for the exemplary symmetry unit.
Fig. 12 illustrates an exemplary symmetry unit.
Fig. 13 illustrates repetitive symmetry units.
Fig. 1~ is a diagrammatic top view of the x-y po~itioner and optical path.
- Fig. 15 is:a diagrammatic side view illustrating the optical path.
, :` :
D~BOriP~iO~ of ~e Pre~erre~ ~mbo6iment The laser cutt~r of the present invention operates under control of a set of signals (i.e.
numeric control) defining the cut lines traversed by the ~oherent radiation generated by the laser.
These signals, herein called a symmetry unit, are created from pre-existing pat~ern graphical information. It is known to electronically store patterns in digital ~ormat. It is also known to use available computer programs to position the patterns to minimize waste (i.e. maximize the use oP the cloth)O The pattern information sig~als represent 6patial (x-y) coordinates which are used to control position in existing x-y positioners for stop-to-cut las~r cutter6.
: The process of defining a symmetxy unit begins by displaying an existing pattern and then re-ordering and re-seguencing the pattern cut lines ~or directing the laser to cut more efficiently.
The process o~ generating the symmetry unit may be performed on an IBM PC or compatible computer with an EGA/VGA color monitor. An IBM
PS/2 computer ~ay al80 be used. The operating system must be DOS 3.0 or higher versions. DOS 3.3 is suitable. All graphical information (both patterns and sequenced symmetry units) is ~tored in the Computer Graphics Metafile (ANSI Standard X3.122 1986). Grap~ical informa~ion may be supplied by a Microdynamics or Auto-Cad program and then converted to CGM format for subs2quent manipulation into symmetry unitr-llumeric controls for opsrating ~he laser cutter. The data represents a set o~ coordinate points, velocity and time.
The first step in the process is to display an existing pattern: that is, a pattern for which sequenced cut lines have not been created. A
typical pattern replica screen ~or a garment sleeve ic ~hown in Fig. 7. The pattern i~ shown in duplicate since repetitive patterns are to be cut.
For purposes o~ explanation, the pattern shown in Fig. 7 is considered to be advancing as on a conveyor from right to left, and out the left side.
The next step i5 to nest the two pattern replicas shown in Fig. 70 This minimizes wa~te by moving the patterns together along the conveyor axi~. The patterns, under program control, are moved only along the conveyor axis. Although it could ~e provided in other circumstances, no vertical or lateral movement of one pattern replica with respect to the o~her is allowed ~ince it is assumed ~hat a tubular piece of cloth is being cut.
(The dotted lines represent the ~olded edges of the cloth.) However, both patterns may be moved laterally (vertically on ~he ~creen) in respect to the conveyor. Fig. 9 shows the two nested patterns. Specifically, the patterns have been moved axially into abutment with each other.
The next step in the process is to generate the symmetry unit, or more particularly to select the cut lines included in a ~ymmetry unit.
As previously noted, a ~ymmetry unit is a minimal set of cut lines of a nested pattern which enable the laser cutter to cut repetitive patterns efficiently, that is, in optimal time. Instead of cutting the original pa~tern, the laser cu~ter cuts all o~ the ~paces between patterns, thus creating the original pattern. Moreover, a symmetry unit does not ne¢essarily cut out a complete pattern, rather it ~ay initially finish cutting the prsvious pattern and start the next pattern, which i6 ¢ompleted by the next repetition o~ the symmetry unit.
.. . . . . . . . . ` .
Symmetry units are explained in more detail by reference to the drawings. Fig. 8 shows a typical sleeve pattern. Since the pattern is to be cut a number of times during a single run of the laser cutter, repetitive illustrations of the sleeve are ~hown representing repetitions o~ the sleeve following each o~her along the longitudinal axis of the tube of cloth. However, cutting actually takes place at only one cut zone. Curved lines are shown in straight line segments because the pattern is built from a ~eries of straight lines. Also the sleeve patterns are shown nested:
that is, moved into end-~o-end abutting relation.
The hatched lines highlight the space between patterns.
Inspection o~ Fig. 8 reveals that it makes no difference to the ultimate result whether the laser cutter cuts each pattern or the space between patterns. In the end, the desired pattern i8 formed. However, there are significant operational advantages to autting the space between pattarns. The problems inherent in repetitively auttin~ a moving piece of material are reduced.
Fig. 8 illustrates how the symmetry unit occupies less space than the pattern. Thus, there is l~ss distance to be traversed while the cloth is moving through a cut zone. A cut zone is the operative area over which the laser cutter can scan the beam of radiation. Inspection of Fig. 8 also reveals that dryhaul i~ minimiz~d because of the proximity of the cut lines to each other. Finally, the problem of in~initely variable multiple repetitions without dri~ting or chasing the pattern out o~ the cut zone is resolved because ~uccessive symmetry units can be linked to each other.
Specifically, the last point of each symmetry unit can always be the first point o~ the next one, and the geometric location of that point remains identical. This is so even if a dryhaul must be added at the end o* a cut in order to link the symmetry unit to the next repetition. Movement of the laser beam by the laser cutter's x-y positioner is synchronized to the conveyor's movement to assure first and last point identity.
Fig. 9 illustrates two nested patterns.
To create a s~mmetry unit, the minimum number of cut lines to cut a complete pattern are selected.
A line may come from either the left or right ,,. ,., : ,,. -, . - , ~
,,~ :,.. . , .. , . ,:, ., , :
pattern as long as every line in the pattern is cut. The highlighted lines in Fig. lo illus~rate the cut lines o~ a ~mmetry unit for the sleeve pattern.
The ~leeve pattern used to exemplify the present invention can be nested close enGugh together that ~hey share 60me lines. Also the 8~W
line which separates one sleeve from the other within a si~gle pattern is really two cut lines, one for each sleeve. There are four such common line segments in the example.pa~tern as shown in Fig. 11 by the highlighting. One o~ each such common or duplicate line segments may be removed.
~owever, not all common cut line egment~ should be removed. For example, the two ~hort common line segments extending to the ~dgelines of the cloth should not b~ modified. The Iaser should be directed to traverse these lines twice because deleting one of the common lines will not improve over all throughput o~ the laser cutter since the x-y positioners will still have to travel ~ack over these lines during cutting. Indeed, removing these lines could actually increase cutting time because the positioner must come to ~ complete halt to turn off the laser.
.. .... ... . : . . . . ~, .. ... . .. . . . . .... . . .
The procedural steps for identifying common line segments in a group of cut lines is to first examine each line selected as part of the sy~metry unit, determine its shape, and pair all lines of equal slope together. All other lines are disregarded. The second step is to calculate the y-intercept of ~ach line in a pair. If the y-intercepts are equal, then the lines are co-linear.
All other pairs are disregar~ed. The third step is t~ examine the end poin~s o~ the lines to determine if they overlap. Three basic cases exist: (1) no overlap; there~ore not a common line; (2) line segments overlap; therefore there is a common line sagment; (3) one line segment is completely inside the second line segment; there~ors there is a common line segment.
~ he ~equence of cut lines followed by the laser is also important. Throughput is enhanced not only by selection of a minimal set of nut lines but also by ordering the sequence in which the cut lines are traversed to be as ef~icient as possible.
The factors which affect cut line se~uence are:
1. A continuously moving conveyor provides the x-y positioners with only a limited amount o~ time and work area in which to cut each line.
Attorniey Docket No 5243-4 ~T~OD ~N~ APPAR~U~ FOR hA8ER CUT~IN~
REPETITIVE PATTBRN8 IN A CONTIN~OU~LY
NOVING 8TREAM OF MATERIA~
Bac~round o~ th~ Invention I. ~iald o~ th Inv~itio~-The present inventlon relatos generally to a method and apparatus for using a laser to cut patterns repetitively in a oontinuous}y moving sheet o~ material.
The known method of laser cutting patterns in a itream o~ ma~erial i8 to sequentially advance the material by a conveyor into a cutting zone, and then while the material is stationary, U9Q an x-y aptical positioner to cut a pattern ~rom the material by moVing a ~ocused beam o~ coherent radiation over the materlal. The beam 1s caused to ~raverse the patt~rn under control of a digital :
:: : :
computer and numeric machine controller which process ~tored data representing the pattern to be cut~ After the pattern is cut, the conveyor starts up to advance cut parts out of, and fresh material into, the cutting zone. Significantly gr~ater throughput can be achieved by laser cutting the patterns if ~he material never stops moving while the cutting takes place.
The present invention is directed to laser cutting patterns in a continuously moving sheet of material. The method of cutting may be characterized as cutting patterns in a moving reference frame. The method and apparatus of the present invention achieves significantly higher throughputs than conventional ~top-to-cutn laser pattern cutting machines because no extra time is needed to move cut parts out of the cutting zone and bring in fre~h material. Also cutting time is reduced by moving the focused laser beam along the conveyor axis in6tead o~ relying only on conveyor movement.
The presen~ invention has particular utility in cutting pa~terns o~ ~abric for mass produced apparel. The advantage-~ of using a laser to cut patterns in fabrio for garments include '~
.
. ~ . : ~ , . . ~
enhanced cutting accuracy, numerical control of the cutting process, little waste, ease of change over to different sizes or patterns and the ability to cut all of the patterns for a single garment out of the same section of cloth. The laser cutting apparatus, however, can efficiently cut only a limited number of layers at a time whereas other pattern cutting devices, such as mechanical cutters, can cut a large number o~ layers to enable increased throughput. This may make them economically competitive with laser cutters when unit production, repeatability and unbundling are not critical. By providing the ability to continuously move material, the present invention enhances the capability of laser cutters to compete with conventional cu~ters by providing increased throughput.
Although the present invention is exemplified by laser cutting patterns in fabric for clothing, it is not so limited. The present invention i6 applicable to cutting patterns in many types o~ continuously moving material where the cutter, such as a focused beam of coherent radiation, can be directed to traverse a repeatable set of cut lines.
;
.: . . . ~ : . . . . .
~ . ~
The present invention is also directed to a device ~or removing material from the conveyor~
When the present laser cutter i6 used to cut cloth, the resultant patterns are highly flexible and difficult to physically manipulate. The present invention provides a device ~or easily and conveniently removing material from the conveyor surface.
II. De3criptio~ o~ th~ Prior Ar~
U.S. Patent No. 3,761,675 for a Material Cutting and Printing System isæued September 25, 1973 to Hughes Aircraft Co. discloses a method and apparatus for cutting material, especially ~abric, using a focused beam of coherent radiation. An x-y positioner under the control of a digital computer scans the beam to cut a pattern in the material.
The computer al60 controls the lasers on-off se~uence. The material is stationary while the pattern is cut.
Laser cutters of the type disclosed in U.S. Patent No. 3,761,675 have been sold by General Systems Research, Inc. o~ Edmonton, Alberta, Canada. These laser cutters use computer programs to generate patterns and control the laser, x-y : . .. . ,~ :,, . . . ~
optical positioner and conveyor. Throughput has been enhanced by using dual laser beams and two or more seguential cutting zones. The conveyor tops while the material is being cut by the laser.
U.S. Patent Nos. 3,811~554 and 3,828,697 for Working Surface for Radiant ~nergy Beam Cutter issued ~ay 21, 1974 and August 13, 1974, respectively, and U.S. Patent No. 3,828,159 issued August 6, 1974 for Laser Cutting Surface disclose honeycomb conveyor slats or ~urfaces which have been used in the prior laser cutters dascribed above.
U.S. Patant No. 3,832,948 for Radiation Method for Making a Surface in Relief issued September 3, 1974 discloses a method and apparatus for making printing plates and other products with an embossed surface by ~canning a beam of csherent radiation over the surface. The on-off sequence for the laser beam is controlled by a dig~tal computer. The printing plate is stationary while its surface is embossed by the cohexent radiation.
,i ., . i . , " . . . . . . ~ ... .. ... .
III. Bum~ar~ o~ the Inve~tion In accordance with the invention, a pattern is repetitively cut by coherent radiation incident on a continuously moving stream of material. A conveyor continuously advances the material through a cutting æone where an electronically controlled x-y positioner traverses ths pot where the coherent radiation is incident on the material through a repetitive set of cut lines. These cut lines, which ultimately define the 6hape of the desired patterns, provide an effici~nt way o~ cutting the pattern in a moving reference frame; that i~, in a continuously moving stream of material~ The terms ~continuous stream"
and ~continuous sheet~ are used interchangeably throughout this description of the invention to mearl material of inde~inite length.
A problem with cutting moving material is that there is a possibility that the positioner will try to ~ollow the material out of the cut zone 1~ the conveyor is moving too rapidly or too 810wly. The problem o~ the positioner drifting out o~ the cut zone is eliminated, in accordance with ~he present invention, synchronizing the sequence o~ cut lines with the conveyor speed so that the positioner returns the beam o~ coherent radiation to the same incident ~pot within the cut zone where it began. To accomplish this result the beam is directed to traverse a repeatable set of lines defining a geometric 6hape, herein called a s~mmetry unit, where the final spot is the starting spot for the next repetition. And the conveyor is controlled to advance the material so that these two points occur at the same location within the cut zone.
Starting and stopping at the Bame spot has a furthsr advantage. The number of pattern repetitions that are going to be cut is entirely variable. Whether it is 5, 15 or 5,000, the Btrategy used to define a symmetry unit must be the ~ame. Starting and stopping the set o~ cut lines at the same spot allows the positioner to cut as many repetitions as desired without drifting out of the cut zone.
Since, in accordance with t~e present lnvention, the conveyor and material move continuously thro~gh the cutting zone, the x-y positioner must compensate for the moving condition ot the conveyor and maintain the same relative veloai~y over the material regardless of the ,~ .. ..
. . : . . . ,, i,,; :~ ; , . , , :
: : ~ : .
direction of motion. Even though the conveyor is moving, the positioner is capable o~ automatically adjusting its ~peed to accommodate the motion and keep the cutting velocity constant with respect to the material. ~hus the control ystem of the present invention i synchronized to the conveyor's movement.
As described in more detail hereinafter, the laser cutter uses a ~equential set of cut lines defining a symmetry unit whose geometric shape represents the space between patterns. This symmetry unit enhances cutting efficiency while also obviating problems inherent to the process of cutting in a moving referenced frame. Because the conveyor is constantly moving while the cutting is taking place there i~ a fini~e amount of time ~o cut each individual line o~ the pattern. To be cut a line must be pre~ent in the cutting zone. Also, a line must be cut before it leaves the cukting zone. The 6ymmetry unit compensates for this problem by minimizing the total length of cut lines and optlmizing their cutting sequence while innuring that oaoh line c~n be cut while it is .
: ' ~ . :
present in the cut zone. The ~ymmetry unit also permits unlimited selection of the number of repeated patterns to be cut.
The set of cut 1 ines within the 6ymmetry unit traver~ed by the incident ~pot of radiation defines the pattern cut in the material. The cut lines selected for the symmetry unit, and their sequenc~, therefore af~ects the capabilities o~ the laser cuttPr. By reducinq the ~otal cut length of a symmetry uni~, the ~ime required to cut a pattern is also reduced, and the cutting process is made more ef~icient assuming a constant cutting velocity. Likewise, efficiency is enhanced by properly ordering the sequence o~ cut lines within a symmetry unit. Also common cut lines need be traversed only once. Thu~ the present invention uses the sy~metry unit to provide a more e~ficient way of cutting a pattern or pattarns in a moving sheet of material.
The symmetry unit of the present invention represents the space between two or more patterns. More particularly, the symmetry unit of the present invention represent~ the minimum number of lines which when cu~ repetitively will produce the desired pattern in the fastest time. Since ,,: :, . - : ,~ ,, ~ -patterns are to be r~petitively cutl and ~ince they are almost always irregular in shape, there is always a certain amount of material between the patterns. ~ather than cut the pattern the x-y positioner causes the coherent radiation to cut the spaces between patterns to create the desired pattern. The result is the ~ame as traversing the pattern itself but the efficiency o~ the cutting process is enhanced. One reason for enhan~ed efficiency is that the perimeter of the space between the patt~rns is less than the perimeter o~
the patterns themselves. By cutting symmetry units it is not necessary to cut out a complete pattern.
Instead the cut lines of a symmetry unit can finish a previous pattern and 6tart the next pattern, which is completed by the next repetition of the symmetry unit. Another way a symmetry unit enhances effi~iency is by minimization o~
~dryhaulN. Dryhaul is when the laser beam has to be turned off to move the beam to a new part of the pattern. Since the cu~ line~ in a 6ymme~ry unit are closQr together than those of a pattern, dryhaul is minimized.
The present invention also provides a device for ef~ectively removing material from the laser cutter's conveyor.
The convsyor surface itself must be specially constructed for use with coherent radiation. Generally, it must be constructed 80 as to support the material for accurate cutting and yet not to be damaged by the radiation. Prior support surfaces have used pins. Hon~ycomb surfaces have also been used to provide a cutting bed. See U.S. Patent Nos. 3,811,554 and 3,828,159.
These ~urfaces, however, do not provide for ready removal of flexible materials such as cloth.
The present invention uses a conveyor ~urface which i8 both suitable ~or use with coherent radiation and cooperates with an apparatus for ~acilitating the removal of the material.
Specifically, the conveyor sur~ace is defined by spaced longitudinally aligned ribs which are suitable for use as a outting ~ed for the in~rared coherent radiation used by the laser cutter. The ribs cooperate with an extractor plate which includes a comb-like edge in inter-spatial engagement with the conveyor ribs. T~e extractor plate pre~erably engages the conveyor at an upward angle to the horizontal so that the pattern pieces slide onto the extractor plats. The pieces are drawn over the extractor plate by a conveyor positioned over its surface. ~his conveyor draws the pattern pieces onto and over the extractor plate.
~r~f De~¢riptlon o~ the Drawing3 For the purpose of illustrating the invention, there is shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.
Fig. 1 is a side elevational view o~ the laser cutter of the present inventionO
FigO 2 is a top plan view of the laser cutter except the laser is not shownO
Fig. 2A is an enlarged plan view of the extractor plate.
Fig. 3 i~ an end view of the laser cutter.
Fig. 4 is an enlarged sectional view of the x-rail and drive motor taken ~rom the aircled portion in Fig. 3.
- . - ~. . . . . . -Fig. 5 is an enlarged partial view of the x-y positioner.
Fig. S i~ a signal ~low diagram for the laser cutter.
Fig. 7 illustrat~s a sleeve pattern as presented on a video monitor.
: Fig. 8 illustrates the relationship between nested, repetitive sleeve patterns.
Fig. 9 illustrates repetitive sleeve patterns as they would appear on an video m~nitor for creation of a ~ym~etry unit.
Fig. 10 illustrates the cut lines for an exemplary symmetry unit.
Fig. 11 illustrates the co~mon lines for the exemplary symmetry unit.
Fig. 12 illustrates an exemplary symmetry unit.
Fig. 13 illustrates repetitive symmetry units.
Fig. 1~ is a diagrammatic top view of the x-y po~itioner and optical path.
- Fig. 15 is:a diagrammatic side view illustrating the optical path.
, :` :
D~BOriP~iO~ of ~e Pre~erre~ ~mbo6iment The laser cutt~r of the present invention operates under control of a set of signals (i.e.
numeric control) defining the cut lines traversed by the ~oherent radiation generated by the laser.
These signals, herein called a symmetry unit, are created from pre-existing pat~ern graphical information. It is known to electronically store patterns in digital ~ormat. It is also known to use available computer programs to position the patterns to minimize waste (i.e. maximize the use oP the cloth)O The pattern information sig~als represent 6patial (x-y) coordinates which are used to control position in existing x-y positioners for stop-to-cut las~r cutter6.
: The process of defining a symmetxy unit begins by displaying an existing pattern and then re-ordering and re-seguencing the pattern cut lines ~or directing the laser to cut more efficiently.
The process o~ generating the symmetry unit may be performed on an IBM PC or compatible computer with an EGA/VGA color monitor. An IBM
PS/2 computer ~ay al80 be used. The operating system must be DOS 3.0 or higher versions. DOS 3.3 is suitable. All graphical information (both patterns and sequenced symmetry units) is ~tored in the Computer Graphics Metafile (ANSI Standard X3.122 1986). Grap~ical informa~ion may be supplied by a Microdynamics or Auto-Cad program and then converted to CGM format for subs2quent manipulation into symmetry unitr-llumeric controls for opsrating ~he laser cutter. The data represents a set o~ coordinate points, velocity and time.
The first step in the process is to display an existing pattern: that is, a pattern for which sequenced cut lines have not been created. A
typical pattern replica screen ~or a garment sleeve ic ~hown in Fig. 7. The pattern i~ shown in duplicate since repetitive patterns are to be cut.
For purposes o~ explanation, the pattern shown in Fig. 7 is considered to be advancing as on a conveyor from right to left, and out the left side.
The next step i5 to nest the two pattern replicas shown in Fig. 70 This minimizes wa~te by moving the patterns together along the conveyor axi~. The patterns, under program control, are moved only along the conveyor axis. Although it could ~e provided in other circumstances, no vertical or lateral movement of one pattern replica with respect to the o~her is allowed ~ince it is assumed ~hat a tubular piece of cloth is being cut.
(The dotted lines represent the ~olded edges of the cloth.) However, both patterns may be moved laterally (vertically on ~he ~creen) in respect to the conveyor. Fig. 9 shows the two nested patterns. Specifically, the patterns have been moved axially into abutment with each other.
The next step in the process is to generate the symmetry unit, or more particularly to select the cut lines included in a ~ymmetry unit.
As previously noted, a ~ymmetry unit is a minimal set of cut lines of a nested pattern which enable the laser cutter to cut repetitive patterns efficiently, that is, in optimal time. Instead of cutting the original pa~tern, the laser cu~ter cuts all o~ the ~paces between patterns, thus creating the original pattern. Moreover, a symmetry unit does not ne¢essarily cut out a complete pattern, rather it ~ay initially finish cutting the prsvious pattern and start the next pattern, which i6 ¢ompleted by the next repetition o~ the symmetry unit.
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Symmetry units are explained in more detail by reference to the drawings. Fig. 8 shows a typical sleeve pattern. Since the pattern is to be cut a number of times during a single run of the laser cutter, repetitive illustrations of the sleeve are ~hown representing repetitions o~ the sleeve following each o~her along the longitudinal axis of the tube of cloth. However, cutting actually takes place at only one cut zone. Curved lines are shown in straight line segments because the pattern is built from a ~eries of straight lines. Also the sleeve patterns are shown nested:
that is, moved into end-~o-end abutting relation.
The hatched lines highlight the space between patterns.
Inspection o~ Fig. 8 reveals that it makes no difference to the ultimate result whether the laser cutter cuts each pattern or the space between patterns. In the end, the desired pattern i8 formed. However, there are significant operational advantages to autting the space between pattarns. The problems inherent in repetitively auttin~ a moving piece of material are reduced.
Fig. 8 illustrates how the symmetry unit occupies less space than the pattern. Thus, there is l~ss distance to be traversed while the cloth is moving through a cut zone. A cut zone is the operative area over which the laser cutter can scan the beam of radiation. Inspection of Fig. 8 also reveals that dryhaul i~ minimiz~d because of the proximity of the cut lines to each other. Finally, the problem of in~initely variable multiple repetitions without dri~ting or chasing the pattern out o~ the cut zone is resolved because ~uccessive symmetry units can be linked to each other.
Specifically, the last point of each symmetry unit can always be the first point o~ the next one, and the geometric location of that point remains identical. This is so even if a dryhaul must be added at the end o* a cut in order to link the symmetry unit to the next repetition. Movement of the laser beam by the laser cutter's x-y positioner is synchronized to the conveyor's movement to assure first and last point identity.
Fig. 9 illustrates two nested patterns.
To create a s~mmetry unit, the minimum number of cut lines to cut a complete pattern are selected.
A line may come from either the left or right ,,. ,., : ,,. -, . - , ~
,,~ :,.. . , .. , . ,:, ., , :
pattern as long as every line in the pattern is cut. The highlighted lines in Fig. lo illus~rate the cut lines o~ a ~mmetry unit for the sleeve pattern.
The ~leeve pattern used to exemplify the present invention can be nested close enGugh together that ~hey share 60me lines. Also the 8~W
line which separates one sleeve from the other within a si~gle pattern is really two cut lines, one for each sleeve. There are four such common line segments in the example.pa~tern as shown in Fig. 11 by the highlighting. One o~ each such common or duplicate line segments may be removed.
~owever, not all common cut line egment~ should be removed. For example, the two ~hort common line segments extending to the ~dgelines of the cloth should not b~ modified. The Iaser should be directed to traverse these lines twice because deleting one of the common lines will not improve over all throughput o~ the laser cutter since the x-y positioners will still have to travel ~ack over these lines during cutting. Indeed, removing these lines could actually increase cutting time because the positioner must come to ~ complete halt to turn off the laser.
.. .... ... . : . . . . ~, .. ... . .. . . . . .... . . .
The procedural steps for identifying common line segments in a group of cut lines is to first examine each line selected as part of the sy~metry unit, determine its shape, and pair all lines of equal slope together. All other lines are disregarded. The second step is to calculate the y-intercept of ~ach line in a pair. If the y-intercepts are equal, then the lines are co-linear.
All other pairs are disregar~ed. The third step is t~ examine the end poin~s o~ the lines to determine if they overlap. Three basic cases exist: (1) no overlap; there~ore not a common line; (2) line segments overlap; therefore there is a common line sagment; (3) one line segment is completely inside the second line segment; there~ors there is a common line segment.
~ he ~equence of cut lines followed by the laser is also important. Throughput is enhanced not only by selection of a minimal set of nut lines but also by ordering the sequence in which the cut lines are traversed to be as ef~icient as possible.
The factors which affect cut line se~uence are:
1. A continuously moving conveyor provides the x-y positioners with only a limited amount o~ time and work area in which to cut each line.
2. Time wa~ted due to dryhaul further res~ricts cutting time and influences the sequ~ncing strategy.
3. The direction of cutting with respec~ to the conveyor af~ects performance of the laser cutter as well as overall cutting time.
4. A cut line must be cut be~ore the material leaves the cut zone.
The ¢riterial sequencing of lines is there~ore a~ follow~ The cut sequence 6hould attempt ts traverse the cut lines which will be the earliest to leave the cut zone. The symmetry unit's cut lines generally should be seguenced left to right: that is, against the direction of movement of the conveyor. Dryhaul cannot alway~ be avoided, but it should be reduced to a minimum.
Consequently, the se~uence should be from le~t to right a~ long as it does not require any extra dryhaul.
.. .. ... .. . : . ., . . . . , . :, .. ..
The cut 1 ine sequence may be arranged in any order 6elected by the machine ~Iser. The choice, however, ~;hould follow the suggested criteria for efficient laser cutting. ~qoreoYer, a cut line may be ~elected once and only onceO
Traversing the ~ame cut line in opposite directions is considered to be two cut lines. A programmed algorithm 6uggests cut lines according to this heuristic .
1. Look for an unselected cut line which shares an end point with the f inal point of the most recently selected line.
2. Look Por the closest unselected cut line to the most recently selected cut line. A cut line is considered ~closest~ by determining the shortest distance from the final point of the last cut line selected to the candidates ' end points .
3. Look for an unselected cut line whose end point is closest to the origin. This cut line will be the first to leave the cut zone.
The foregoing rules should be followed in the order given but may be reversed.
The algorithm for selecting the end points ia actually a selection of the direction in which the cut iB to be made since the end point ., . ,,. . ~, ,. . . , ,.... i . i ~ .
coordinates are already known as part of the graphical data. ~he cut direction i~ therefore determined by selecting the starting point. The rule for ~election is to choose a~ the cut line starting end point an end point that shares its location with the last point of the previously selected cut line, i~ any.
Fig. 12 shows the symmetry unit for the sleeve patterns. Point 20 is both ~he start and stop position.
As explained above, the x-y positioner must return the laser beam to the same position within the cutting zone where cutting began~ This may necessitate adding a dryhaul (non-cutting line) to the cut path. Whether a final dryhaul is required is determined by comparing seyuential symmetry units as shown in Fig. 13. A program calculates the relative distance from the last point 22 of the first symmetry uni~ to the ~irst point 24 of the second symmetry unit. Point 24 i~
by dafinition the same as point 20. A dryhaul is then added to link the two units. Thus, the x-y positioner 66 will star~- and end its motion at the same point relative to the symmetry unit.
.: ; . . :.
To synchronize the start-stop point to the conveyor, it is nece~sary to determine conveyor velo~ity. If the time to trace a symmetry unik is t, and the absolute distance from the start point to the end point is ~, then the conveyed material velocity is s/t. By advancing the conveyor at this velocity, the laser cutt r can cut any selected number of symmetry units without leaving t~e cutting zone.
In order to control the physical natura of the cut or kerf actually made by the laser, the laser should always traverse the material being cut at a con~tant velocity. Thus, the power of the coherent radiation on the material remains constant. The conveyor i8 set to move at a constant velocity. Accordingly, the x-y positioner slows down in the x-direction when cutting against the direction of the conveyor motion. It has to speed up when cutting in the direction of the convey~r motion. Hence all cutting should be done against the direction of the conveyor's mo~ion to tho extene po~sible.
, Figs. 1, 2 and 3 illustrate the laser cutter apparatu6 60 of the present inventionO
Laser cutter 60 includes a rigid super structure 62, a conveyor 64, x-y po~itioner 66, exhaust system 68 and laser 130.
Super tructure 62 is mad~ to ~upport the optical positioner, laser an~ conveyor in as near Yibration ~ree relation as possible for accurate cutting. It includes vertical columns 70 and 72 at spaced intervals. Columns 70 a~d 72 are visible in Fig. 3. Super structure 62 also includes horizontal cross-pieces, such as cross-piece 74, joinin~ horizontal side-pieces 76 and 78. Columns and cros~-pieces are braced by trusse6, such as trusses 80 and 82. ~ubular steel and I-beams are used ~or the super structure to provide rigidity.
The rails for the x-y optical positioner 66 are rigidly mounted on cross-pi~ces 84 and side pieces 86, 88 welded to support pieces ~0 mounted in the columns.
Convsyor 64 comprlses rectangular slats ~2 hingedly ~oined to the conveyor. The con~eyor i~ supported by slides (not shown) and rotatably mounted pulleys 98, 100 at each end o~ the conveyor. The conveyor is driven by chains ~4, 96 passing over sprockets 102, 104, 106 and 108.
Sprockets 102, 108 are driven by an a-c electric motor (not show~).
Each o~ the slats comprises a set of elongated ribs llo aligned with the longitudinal axis of the conveyor. Ribs 110 are made o~ brass.
Brass is chosen because it re~lects the coherent infrared radiation (wavelength 10.6 microns) used in the laser cutter 60. 8rass is also selacted because it has good heat transfer properties.
Copper may also be used. The ribs are mounted with one side edge at the support surface of the conveyor, and are spaced apart 0.375 inches ~or extraction of the cut pieces as hereinafter explained. Each rib i~ .025 inches thick.
Exhaust 6ystem 68 provides hood 114 below the conveyor ~or drawing gaseous emissions away from the cutting zone.
x-y positioner 66 comprises y-rail 116 upon which is mounted carrier 142 supporting ~ocusing optiaal systems 118, 120, and adjustable 45~ mirrors 122, 124 for directing and focusing dual beams of coherent radiation on the material tran~ported by the conveyor 64. Dual beams are used so two patterns can be cut at once.
.. . , . . - .: , : .. ., . .. , ~ , ~
Adjustable mirrors 126, 128 mounted on the y-rail at 45 to the longitudinal axis of the conveyor re~lect the coherent radiation to mirrors 122, 124 mounted on carrier 142.
The ~ource of coherent radiation i~ laiser 130 mounted to the top of super structure 62.
Laser 130 is a dual beam CO2 CW Liaser. By way o~
example, laser 130 may be a ~odulase 800 C02 CW
Laser available from GSR Technologies, Ltd. of Edmonton, Alberta, Canada. Thiis laser produces two beams of infrared radiation at a wavelength of 10.6 micron~ at a rated power of 400 watts. Each beam at the output coupler is 7.5 mm with a divergence of 1.8 mrad.
As shown ~chematically in Figs. 14 and 15, the two coherent radiation beams 132 and 134 genorated by laser ~30 are reflected downwardly by 45 mirrors, only mirror 136 being ~hown. Mirrors 138 and 140 located toward the feed end of conveyor 64 dir~ct the radiation beams horizontally and axially toward mirrors 126 and 128. Mirror~ 12~
and 1~8 direct the light parallel to y-beam 116 to mirrors 122, 124 which direct the radiation through the focusing optlcs 118, 120 to the conveyor ~ur~ace.
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; , . :. .: . ~ : :: . , , - : : : .:
., . . . . ,: : : . , . - .. . .: .. . .. . . . ,: ..
. .. . - ~ . .
As shown in Fig. 3, the 45O mirr~rs 122, 124 and ~ocusiny op~ics 118, 120 are mounted on the carrier 1~2. Carrier 142 i8 slidably engaged with and supported by y-rail 116~ Carrier 142 also supports y-mo~or 1~4 whose output ~haf~ 145 drives pinion 147 engaged with the rack 151 fixed to y~
rail 116. See Fig. 5. The mo~or 144 moves th~
carrier 142 along y-rail 116, and hence shiPts the coherent radiation transversely or across the conveyor surface. Such transverse motion may als~
be re~erred to as the y-direction.
Movement along the conveyor's longitudinal axis is accomplished by moving the y-rail 116 along the x-rails 117 and 1~9. As shown in Fig. 4, y-rail 116 iB movably mounted on x-rail 117 by slide 146. x-rail 117 i joined to angle piece 148 which is fixed to side piece 88. x-rail 119 is attached to side piece ~9. Both x-rails 117, 119 extend along the conveyor a sufficient length so that y-rail 116 can be traversed over the full length of the outting zone, which may be by way o~ example 60 inches. y-rail 116 also supports x-motor 150 whose output shaPt 152 drives pinion 154. Rack 156 i~ mounted on angle piece 148 and is engaged by pinion 154. Thus, x-mo~or 150 moves y-.` ' ' ~ '' , . ' ., ' .. ' ' ` ' ' ' , rail 116 to any desired position along thelongitudinal axis o~ the conveyor, just as y-motor I44 moves the carrier 142 to any desired transverse position along the y rail. Bo~h motors, functioning under control of the electronic x-y controllers de cribed herein, ~unction to cause the coherent radia~ion to cut material on the conveyor surf~ce. The sequence o~ cut lines followed by the coherent radiation is, in accordance with this invention, a ~ymmetry unit.
Fig. 6 ~hows the signal ~low for the laser cutter 60. The geometric pattern information, that is the symmetry unit machine control information, is loaded into computer 160.
By way of example, computer 1~0 may be a Zenith 380/40 computer with a IBY 7534 touch Gcreen monitor. The control information represents graphiaal data (i.e. coordinate points for the cut lines in a symmetry unit). It also includes velocity information based upon the physical limitations o~ the laser cutter 60. Specifically, velocity is calculatad ba~ed upon the maximum acceleration of the moving elements o~ the x-y .... . .. : : :: :. :.- .: : . . . - . . : .
positioner 66 and the properties of the material to be cut. Thus, each cut line is in fac~ a vector in that it has bo~h dlrection and magnitude.
The x~y positioner operate~ under the control of the Smart Motion Control Card (SMCC) 162 available from Delta Tau Data Systems Inc. of Canago Park, CA. The conveyor operates under the control of the SMCC 164 available from the same manufacturer. Each SMCC conver~s digital data provided by the computer into command ~ignals ~or driving the x-motor 150, y-motor 144 and conveyor motor 166. SMCC 162 provides both x-axi~ and y-axis control for the x-y positioner. SMCC 164 provide6 only x-axis control for the conveyor.
The ~pecific digital data from computer 160 (the command signals) comprises for each cut line vector:
- 1. the end position for the x-motor and y-motor (which together define the end position for the beam of coherent radiation~:
2. the x-motor and y-motor end velocity:
3. the time to get to the end position.
Thase command signals are processed by the SMCC
cards.
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.. , .~ .. . . , ., ~ , . . . . .. .
~ - }
Once a ~mmetry unit has been sequenced an~ the ~inal dryhaul added (if nec~ssary), this cutting info~mation is translated into numeric control commands unders~andable by each SMCC. In addition to the geometry of each vector, these numeric control command~ also contain velocity and timing information used to control the positioner.
Motion information such as maximum acceleration, cutting velocity, laser dwell time and tube overcut are dependent on the target material and are added to the pattern data at cut time. The individual vectors or cut lines of a pattern are described in numeric control commands by acceleration, constant velocity and ~eceleration move commands to insure that the x-y posi~ioner does not exceed these limits. I.aser beam on/of f commands are added to insure that the laser comes on at the right time.
once the numeric control data ~or the symmetry unit are provided, the conveyor velocity is set to insure that the positioners will return to the same location within the cut zone. The computer controls the starting and stopping of the machine, but the SMCC's is responsible for the movement of the x-y positioner along the cut path.
The output o~ SMCC 162 includes x-axis control signals for x-axi~ vel~city control unit (VCU) 168 and y-axis control signals for y-axis velocity control uni~ (VCU~ 170. These are x-axis and y-axis velocity status control signals.
Speci~ically, ~he x-axis and y-axis control ~ignals control each VCU'~ amplifier and hence the frequency and voltage for energizing the x-motor 150 and y-motor 144. Each SMCC 162 functions as a servo-controller. The x-motor 150 and the y-motor 144 are a-c motors and are each coupled to an optical encoder 172 and 17~, respectively. Each encoder 172, 174 feeds back a pulsed motion signal (e.g. 2,000 pulse per 360 revolution o~ the motor) to its respective VCU and to the S~CC 1620 The SMCC r~ads the encoder ~eedback signals, which represent where the beam of radiation is on both the x-axis and y-axi~. The SMCC calculat~ where the beam should be based on the command signals.
The SMCC then generates frequency and voltage command ~ignals which ara converted into actual chan~es in frequency and voltage to con~rol the velocity of the x-motor 150 and y-motor 144.
- 33 ~
The x-y positioner is synchronized to the conveyor. SMCC 164 controls the conveyor's velocity. Conveyor velocity is adjustable to provide sufficient time to cut each pattern.
However, the select~d csnveyor velocity is maintained constant while the x-y positioner is tracing a symmetry unit, and each repetition thereof. As with the x-y positioner, the conveyor is driven by an a-c motor 16~ coupled to an optical encoder 176 whose resolution is also 2,000 pulses per 360. The output signal of encoder 176 is fed back to conveyor VCU 178 and also ~o both conveyor SMCC 164 and x-y positioner SMCC 162. As thus con~igured, SMCC 164 maintains the conveyor at the constant velocity selected for the particular symmetry unit being cuk. Thus, accuracy in returning the x-y positioner to the same starting point for each repetition of a symmetry unit is provided.
Computer 160 also provides on-off control signals ~or the laser 130 as is required for dryhaul.
As best shown in Figs. 1, 2 and 2A, the extractor device 180 for removing cut pieces from conveyor 64 aomprises extractor plate 182 positioned at an acute angle to the horizontal.
Extractor plate 182 includes a planar extension plate 184 and integral teeth 186 extending in comb like fashion across the receiving edge o~ the extractor plate. Teeth 186 are positioned so that the ribs 11) in each conveyor slat pass betwee~
them. ~hus, each pattern piece is literally combed from the conveyor onto the extractor plate.
The extractor plate 182 is supported on slides tnot shown) so that it may be adjustably positioned between khe ribs 110 or even removed therefrom.
Removal of the pattern pieces is assisted by the extractor conveyor 1~8. Extractor conveyor 188 consists o~ a conveyor frame 190 supporting a driven and idler roller upon which are carried æpaced belt~ 192 which engage the pattern pieces and pull them over the extractor plate. There are 16 belts regularly spaced across the width of the conveyor. Sprockets are driven by chains 94 and 96. Sprockets 194 are ~ixed to the same shaft as the chain driven sprockets and drive chains 196 which drives ~prockets 198 ~ixed on the shaft for the drlven roller, thus driving the belts 192.
Gearing ~or the sprockets is sek to move the belts .
, 192 at a lightly faster velocity than the conveyor; e.g. 1% ~aster. Thus, the pattern pieces are moved away from the conveyor for collection and further processing.
The extra¢t~r plate in engagement with the elongated, longitudinally extending ribs 110 provides an ef~ective way to remove cloth and other flexible materials from a conveyor which also serves as an e~fective cutting bed for a laser cutter, The present invention may be embodied in other specific forms without departing ~rom the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.
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... . ~.. . . . . I ~ . .. . - . .. . . . . . ..
The ¢riterial sequencing of lines is there~ore a~ follow~ The cut sequence 6hould attempt ts traverse the cut lines which will be the earliest to leave the cut zone. The symmetry unit's cut lines generally should be seguenced left to right: that is, against the direction of movement of the conveyor. Dryhaul cannot alway~ be avoided, but it should be reduced to a minimum.
Consequently, the se~uence should be from le~t to right a~ long as it does not require any extra dryhaul.
.. .. ... .. . : . ., . . . . , . :, .. ..
The cut 1 ine sequence may be arranged in any order 6elected by the machine ~Iser. The choice, however, ~;hould follow the suggested criteria for efficient laser cutting. ~qoreoYer, a cut line may be ~elected once and only onceO
Traversing the ~ame cut line in opposite directions is considered to be two cut lines. A programmed algorithm 6uggests cut lines according to this heuristic .
1. Look for an unselected cut line which shares an end point with the f inal point of the most recently selected line.
2. Look Por the closest unselected cut line to the most recently selected cut line. A cut line is considered ~closest~ by determining the shortest distance from the final point of the last cut line selected to the candidates ' end points .
3. Look for an unselected cut line whose end point is closest to the origin. This cut line will be the first to leave the cut zone.
The foregoing rules should be followed in the order given but may be reversed.
The algorithm for selecting the end points ia actually a selection of the direction in which the cut iB to be made since the end point ., . ,,. . ~, ,. . . , ,.... i . i ~ .
coordinates are already known as part of the graphical data. ~he cut direction i~ therefore determined by selecting the starting point. The rule for ~election is to choose a~ the cut line starting end point an end point that shares its location with the last point of the previously selected cut line, i~ any.
Fig. 12 shows the symmetry unit for the sleeve patterns. Point 20 is both ~he start and stop position.
As explained above, the x-y positioner must return the laser beam to the same position within the cutting zone where cutting began~ This may necessitate adding a dryhaul (non-cutting line) to the cut path. Whether a final dryhaul is required is determined by comparing seyuential symmetry units as shown in Fig. 13. A program calculates the relative distance from the last point 22 of the first symmetry uni~ to the ~irst point 24 of the second symmetry unit. Point 24 i~
by dafinition the same as point 20. A dryhaul is then added to link the two units. Thus, the x-y positioner 66 will star~- and end its motion at the same point relative to the symmetry unit.
.: ; . . :.
To synchronize the start-stop point to the conveyor, it is nece~sary to determine conveyor velo~ity. If the time to trace a symmetry unik is t, and the absolute distance from the start point to the end point is ~, then the conveyed material velocity is s/t. By advancing the conveyor at this velocity, the laser cutt r can cut any selected number of symmetry units without leaving t~e cutting zone.
In order to control the physical natura of the cut or kerf actually made by the laser, the laser should always traverse the material being cut at a con~tant velocity. Thus, the power of the coherent radiation on the material remains constant. The conveyor i8 set to move at a constant velocity. Accordingly, the x-y positioner slows down in the x-direction when cutting against the direction of the conveyor motion. It has to speed up when cutting in the direction of the convey~r motion. Hence all cutting should be done against the direction of the conveyor's mo~ion to tho extene po~sible.
, Figs. 1, 2 and 3 illustrate the laser cutter apparatu6 60 of the present inventionO
Laser cutter 60 includes a rigid super structure 62, a conveyor 64, x-y po~itioner 66, exhaust system 68 and laser 130.
Super tructure 62 is mad~ to ~upport the optical positioner, laser an~ conveyor in as near Yibration ~ree relation as possible for accurate cutting. It includes vertical columns 70 and 72 at spaced intervals. Columns 70 a~d 72 are visible in Fig. 3. Super structure 62 also includes horizontal cross-pieces, such as cross-piece 74, joinin~ horizontal side-pieces 76 and 78. Columns and cros~-pieces are braced by trusse6, such as trusses 80 and 82. ~ubular steel and I-beams are used ~or the super structure to provide rigidity.
The rails for the x-y optical positioner 66 are rigidly mounted on cross-pi~ces 84 and side pieces 86, 88 welded to support pieces ~0 mounted in the columns.
Convsyor 64 comprlses rectangular slats ~2 hingedly ~oined to the conveyor. The con~eyor i~ supported by slides (not shown) and rotatably mounted pulleys 98, 100 at each end o~ the conveyor. The conveyor is driven by chains ~4, 96 passing over sprockets 102, 104, 106 and 108.
Sprockets 102, 108 are driven by an a-c electric motor (not show~).
Each o~ the slats comprises a set of elongated ribs llo aligned with the longitudinal axis of the conveyor. Ribs 110 are made o~ brass.
Brass is chosen because it re~lects the coherent infrared radiation (wavelength 10.6 microns) used in the laser cutter 60. 8rass is also selacted because it has good heat transfer properties.
Copper may also be used. The ribs are mounted with one side edge at the support surface of the conveyor, and are spaced apart 0.375 inches ~or extraction of the cut pieces as hereinafter explained. Each rib i~ .025 inches thick.
Exhaust 6ystem 68 provides hood 114 below the conveyor ~or drawing gaseous emissions away from the cutting zone.
x-y positioner 66 comprises y-rail 116 upon which is mounted carrier 142 supporting ~ocusing optiaal systems 118, 120, and adjustable 45~ mirrors 122, 124 for directing and focusing dual beams of coherent radiation on the material tran~ported by the conveyor 64. Dual beams are used so two patterns can be cut at once.
.. . , . . - .: , : .. ., . .. , ~ , ~
Adjustable mirrors 126, 128 mounted on the y-rail at 45 to the longitudinal axis of the conveyor re~lect the coherent radiation to mirrors 122, 124 mounted on carrier 142.
The ~ource of coherent radiation i~ laiser 130 mounted to the top of super structure 62.
Laser 130 is a dual beam CO2 CW Liaser. By way o~
example, laser 130 may be a ~odulase 800 C02 CW
Laser available from GSR Technologies, Ltd. of Edmonton, Alberta, Canada. Thiis laser produces two beams of infrared radiation at a wavelength of 10.6 micron~ at a rated power of 400 watts. Each beam at the output coupler is 7.5 mm with a divergence of 1.8 mrad.
As shown ~chematically in Figs. 14 and 15, the two coherent radiation beams 132 and 134 genorated by laser ~30 are reflected downwardly by 45 mirrors, only mirror 136 being ~hown. Mirrors 138 and 140 located toward the feed end of conveyor 64 dir~ct the radiation beams horizontally and axially toward mirrors 126 and 128. Mirror~ 12~
and 1~8 direct the light parallel to y-beam 116 to mirrors 122, 124 which direct the radiation through the focusing optlcs 118, 120 to the conveyor ~ur~ace.
.
; , . :. .: . ~ : :: . , , - : : : .:
., . . . . ,: : : . , . - .. . .: .. . .. . . . ,: ..
. .. . - ~ . .
As shown in Fig. 3, the 45O mirr~rs 122, 124 and ~ocusiny op~ics 118, 120 are mounted on the carrier 1~2. Carrier 142 i8 slidably engaged with and supported by y-rail 116~ Carrier 142 also supports y-mo~or 1~4 whose output ~haf~ 145 drives pinion 147 engaged with the rack 151 fixed to y~
rail 116. See Fig. 5. The mo~or 144 moves th~
carrier 142 along y-rail 116, and hence shiPts the coherent radiation transversely or across the conveyor surface. Such transverse motion may als~
be re~erred to as the y-direction.
Movement along the conveyor's longitudinal axis is accomplished by moving the y-rail 116 along the x-rails 117 and 1~9. As shown in Fig. 4, y-rail 116 iB movably mounted on x-rail 117 by slide 146. x-rail 117 i joined to angle piece 148 which is fixed to side piece 88. x-rail 119 is attached to side piece ~9. Both x-rails 117, 119 extend along the conveyor a sufficient length so that y-rail 116 can be traversed over the full length of the outting zone, which may be by way o~ example 60 inches. y-rail 116 also supports x-motor 150 whose output shaPt 152 drives pinion 154. Rack 156 i~ mounted on angle piece 148 and is engaged by pinion 154. Thus, x-mo~or 150 moves y-.` ' ' ~ '' , . ' ., ' .. ' ' ` ' ' ' , rail 116 to any desired position along thelongitudinal axis o~ the conveyor, just as y-motor I44 moves the carrier 142 to any desired transverse position along the y rail. Bo~h motors, functioning under control of the electronic x-y controllers de cribed herein, ~unction to cause the coherent radia~ion to cut material on the conveyor surf~ce. The sequence o~ cut lines followed by the coherent radiation is, in accordance with this invention, a ~ymmetry unit.
Fig. 6 ~hows the signal ~low for the laser cutter 60. The geometric pattern information, that is the symmetry unit machine control information, is loaded into computer 160.
By way of example, computer 1~0 may be a Zenith 380/40 computer with a IBY 7534 touch Gcreen monitor. The control information represents graphiaal data (i.e. coordinate points for the cut lines in a symmetry unit). It also includes velocity information based upon the physical limitations o~ the laser cutter 60. Specifically, velocity is calculatad ba~ed upon the maximum acceleration of the moving elements o~ the x-y .... . .. : : :: :. :.- .: : . . . - . . : .
positioner 66 and the properties of the material to be cut. Thus, each cut line is in fac~ a vector in that it has bo~h dlrection and magnitude.
The x~y positioner operate~ under the control of the Smart Motion Control Card (SMCC) 162 available from Delta Tau Data Systems Inc. of Canago Park, CA. The conveyor operates under the control of the SMCC 164 available from the same manufacturer. Each SMCC conver~s digital data provided by the computer into command ~ignals ~or driving the x-motor 150, y-motor 144 and conveyor motor 166. SMCC 162 provides both x-axi~ and y-axis control for the x-y positioner. SMCC 164 provide6 only x-axis control for the conveyor.
The ~pecific digital data from computer 160 (the command signals) comprises for each cut line vector:
- 1. the end position for the x-motor and y-motor (which together define the end position for the beam of coherent radiation~:
2. the x-motor and y-motor end velocity:
3. the time to get to the end position.
Thase command signals are processed by the SMCC
cards.
.
.. , .~ .. . . , ., ~ , . . . . .. .
~ - }
Once a ~mmetry unit has been sequenced an~ the ~inal dryhaul added (if nec~ssary), this cutting info~mation is translated into numeric control commands unders~andable by each SMCC. In addition to the geometry of each vector, these numeric control command~ also contain velocity and timing information used to control the positioner.
Motion information such as maximum acceleration, cutting velocity, laser dwell time and tube overcut are dependent on the target material and are added to the pattern data at cut time. The individual vectors or cut lines of a pattern are described in numeric control commands by acceleration, constant velocity and ~eceleration move commands to insure that the x-y posi~ioner does not exceed these limits. I.aser beam on/of f commands are added to insure that the laser comes on at the right time.
once the numeric control data ~or the symmetry unit are provided, the conveyor velocity is set to insure that the positioners will return to the same location within the cut zone. The computer controls the starting and stopping of the machine, but the SMCC's is responsible for the movement of the x-y positioner along the cut path.
The output o~ SMCC 162 includes x-axis control signals for x-axi~ vel~city control unit (VCU) 168 and y-axis control signals for y-axis velocity control uni~ (VCU~ 170. These are x-axis and y-axis velocity status control signals.
Speci~ically, ~he x-axis and y-axis control ~ignals control each VCU'~ amplifier and hence the frequency and voltage for energizing the x-motor 150 and y-motor 144. Each SMCC 162 functions as a servo-controller. The x-motor 150 and the y-motor 144 are a-c motors and are each coupled to an optical encoder 172 and 17~, respectively. Each encoder 172, 174 feeds back a pulsed motion signal (e.g. 2,000 pulse per 360 revolution o~ the motor) to its respective VCU and to the S~CC 1620 The SMCC r~ads the encoder ~eedback signals, which represent where the beam of radiation is on both the x-axis and y-axi~. The SMCC calculat~ where the beam should be based on the command signals.
The SMCC then generates frequency and voltage command ~ignals which ara converted into actual chan~es in frequency and voltage to con~rol the velocity of the x-motor 150 and y-motor 144.
- 33 ~
The x-y positioner is synchronized to the conveyor. SMCC 164 controls the conveyor's velocity. Conveyor velocity is adjustable to provide sufficient time to cut each pattern.
However, the select~d csnveyor velocity is maintained constant while the x-y positioner is tracing a symmetry unit, and each repetition thereof. As with the x-y positioner, the conveyor is driven by an a-c motor 16~ coupled to an optical encoder 176 whose resolution is also 2,000 pulses per 360. The output signal of encoder 176 is fed back to conveyor VCU 178 and also ~o both conveyor SMCC 164 and x-y positioner SMCC 162. As thus con~igured, SMCC 164 maintains the conveyor at the constant velocity selected for the particular symmetry unit being cuk. Thus, accuracy in returning the x-y positioner to the same starting point for each repetition of a symmetry unit is provided.
Computer 160 also provides on-off control signals ~or the laser 130 as is required for dryhaul.
As best shown in Figs. 1, 2 and 2A, the extractor device 180 for removing cut pieces from conveyor 64 aomprises extractor plate 182 positioned at an acute angle to the horizontal.
Extractor plate 182 includes a planar extension plate 184 and integral teeth 186 extending in comb like fashion across the receiving edge o~ the extractor plate. Teeth 186 are positioned so that the ribs 11) in each conveyor slat pass betwee~
them. ~hus, each pattern piece is literally combed from the conveyor onto the extractor plate.
The extractor plate 182 is supported on slides tnot shown) so that it may be adjustably positioned between khe ribs 110 or even removed therefrom.
Removal of the pattern pieces is assisted by the extractor conveyor 1~8. Extractor conveyor 188 consists o~ a conveyor frame 190 supporting a driven and idler roller upon which are carried æpaced belt~ 192 which engage the pattern pieces and pull them over the extractor plate. There are 16 belts regularly spaced across the width of the conveyor. Sprockets are driven by chains 94 and 96. Sprockets 194 are ~ixed to the same shaft as the chain driven sprockets and drive chains 196 which drives ~prockets 198 ~ixed on the shaft for the drlven roller, thus driving the belts 192.
Gearing ~or the sprockets is sek to move the belts .
, 192 at a lightly faster velocity than the conveyor; e.g. 1% ~aster. Thus, the pattern pieces are moved away from the conveyor for collection and further processing.
The extra¢t~r plate in engagement with the elongated, longitudinally extending ribs 110 provides an ef~ective way to remove cloth and other flexible materials from a conveyor which also serves as an e~fective cutting bed for a laser cutter, The present invention may be embodied in other specific forms without departing ~rom the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.
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... . ~.. . . . . I ~ . .. . - . .. . . . . . ..
Claims (20)
1. Apparatus for repetitively cutting a geometric patterns in continuously moving stream of material, comprising:
transport means for continuously advancing the material in which the geometric patterns are to be repetitively cut through a cutting zone;
a laser for generating a beam of coherent radiation for cutting the pattern in the material;
optical means for directing the beam of coherent radiation onto the material in the cutting zone;
said optical means including an x-y positioner for shifting the beam of coherent radiation where it is incident on the material along a sequence of lines to be cut in the material;
means for directing the x-y positioner in timed relation to the continuous movement of the transport means to cause the c-oherent radiation to repeatedly cut the sequence of lines in the material as it is advanced by the transport means through the cutting zone.
transport means for continuously advancing the material in which the geometric patterns are to be repetitively cut through a cutting zone;
a laser for generating a beam of coherent radiation for cutting the pattern in the material;
optical means for directing the beam of coherent radiation onto the material in the cutting zone;
said optical means including an x-y positioner for shifting the beam of coherent radiation where it is incident on the material along a sequence of lines to be cut in the material;
means for directing the x-y positioner in timed relation to the continuous movement of the transport means to cause the c-oherent radiation to repeatedly cut the sequence of lines in the material as it is advanced by the transport means through the cutting zone.
2. Apparatus in accordance with claim 1 wherein said means for directing the x-y positioner includes means for shifting the beam of coherent radiation along a sequence of cut lines that commence and end at the same spot within the cutting zone.
3. Apparatus in accordance with claim 1 wherein the means for directing the x-y positioner includes means to sequentially shift the beam of coherent radiation through a set of cut lines defining a symmetry unit;
each symmetry unit comprising a set of cut lines and dryhaul lines as necessary whose geometry defines the area between two desired patterns being cut in the material.
each symmetry unit comprising a set of cut lines and dryhaul lines as necessary whose geometry defines the area between two desired patterns being cut in the material.
4. Apparatus in accordance with claim 3 wherein the set of cut lines defining a symmetry unit includes lines which complete the cutting of one pattern and start the cutting of the next pattern.
5. Apparatus in accordance with claim 4 wherein the means for directing the optical positioner includes means for shifting the beam of coherent radiation within a symmetry unit to commence and end at the same spot.
6. Apparatus in accordance with claim 4 wherein said means for directing the x-y positioner includes means for shifting the beam of coherent radiation through a set of cut lines and dryhaul lines as necessary defining a symmetry unit wherein the last spot of a symmetry unit is the starting spot of the next symmetry unit, whereby an unlimited number of the desired pattern may be sequentially cut.
7. Apparatus in accordance with claims 1 or 6 including means for shifting the beam of coherent radiation where it is incident on the material at a constant velocity over the moving material relative to its direction of movement.
8. A process for repetitively cutting patterns in a continuously moving stream of material, comprising:
continuously advancing the material in which the patterns are to be repetitively cut through a cutting zone;
directing coherent radiation onto said material to cut the pattern therein;
repetitively shifting the spot where the coherent radiation is incident on the material along a sequential set of lines within the cutting zone in timed relation to the movement of the material to sequentially cut repetitive shapes in the material.
continuously advancing the material in which the patterns are to be repetitively cut through a cutting zone;
directing coherent radiation onto said material to cut the pattern therein;
repetitively shifting the spot where the coherent radiation is incident on the material along a sequential set of lines within the cutting zone in timed relation to the movement of the material to sequentially cut repetitive shapes in the material.
9. The process in accordance with claim 8 wherein the sequence of lines followed by the coherent radiation begins and ends at the same spot within the cutting zone.
10. The process in accordance with claims 8 or 9 wherein the shape of the lines formed in the material is the area between two desired patterns being formed in the material.
11. The process in accordance with claim 8 wherein the sequence of lines completes the cutting of one geometric shape and commences the cutting of the next geometric shape.
12. The process in accordance with claim 10 wherein the area between patterns are minimized by longitudinally, axially nesting the trailing edge of one such pattern with the leading edge of the following pattern to at least partially abut the leading and trailing edge lines of the patterns whereby the distance travelled by the spot of coherent radiation along the set of lines is minimized.
13. The process in accordance with claim 8 wherein the set of lines followed by the spot defines a symmetry unit, the geometry of each symmetry unit defining the area between two desired patterns being cut in the material.
14. The process in accordance with claim 13 wherein the last position of a spot in a symmetry unit is the starting position of the spot in the next symmetry unit.
15. The process in accordance with claim 13 or 14 wherein selected common lines between adjacent desired geometric shapes in the material are traversed only once by the spot.
16. The process in accordance with claim 8 wherein the spot traverses the set of lines at a constant velocity relative to the moving material.
17. The process in accordance with claim 14 wherein the sequential order of lines in a symmetry unit traversed by the spot generally follows the order in which the lines will move out of the cutting zone.
18. The process in accordance with claim 14 wherein the set of lines comprising a symmetry unit include lines wherein the coherent radiation cuts the material and lines where no cutting is effected.
19. The process in accordance with claim 18 wherein the distance along the lines of the symmetry unit where no cutting is effected is minimized.
20. Apparatus for removing cut material.
from a laser cutter, comprising:
a laser cutter including a conveyor, said conveyor including a cutting bed for supporting material to be cut by a laser, said cutting bed comprising side-by-side slats pivotally joined to the conveyor, each slat comprising a set of spaced apart elongated ribs extending parallel to the longitudinal axis of the conveyor, an extractor plate for receiving cut material, said extractor plate being positioned at the delivery end of the conveyor and including a comb-like set of teeth extending from the plate, said extractor plate teeth being positioned such that the slat ribs pass between them, and an extractor conveyor positioned with one flight generally parallel to and in juxtoposition to the surface of the extractor plate for drawing cut patterns across the extractor plate.
from a laser cutter, comprising:
a laser cutter including a conveyor, said conveyor including a cutting bed for supporting material to be cut by a laser, said cutting bed comprising side-by-side slats pivotally joined to the conveyor, each slat comprising a set of spaced apart elongated ribs extending parallel to the longitudinal axis of the conveyor, an extractor plate for receiving cut material, said extractor plate being positioned at the delivery end of the conveyor and including a comb-like set of teeth extending from the plate, said extractor plate teeth being positioned such that the slat ribs pass between them, and an extractor conveyor positioned with one flight generally parallel to and in juxtoposition to the surface of the extractor plate for drawing cut patterns across the extractor plate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2016554 CA2016554A1 (en) | 1990-05-11 | 1990-05-11 | Method and apparatus for laser cutting repetitive patterns in a continuously moving stream of material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2016554 CA2016554A1 (en) | 1990-05-11 | 1990-05-11 | Method and apparatus for laser cutting repetitive patterns in a continuously moving stream of material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2016554A1 true CA2016554A1 (en) | 1991-11-11 |
Family
ID=4144963
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2016554 Abandoned CA2016554A1 (en) | 1990-05-11 | 1990-05-11 | Method and apparatus for laser cutting repetitive patterns in a continuously moving stream of material |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2016554A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5867392A (en) * | 1993-07-15 | 1999-02-02 | Lectra Systemes | Method for marking or cutting a material along predetermined paths |
| WO1999028798A2 (en) * | 1997-12-02 | 1999-06-10 | Lacent Technologies Inc. | Gantry-mounted laser nozzle and method for controlling laser positioning |
| EP1321839A2 (en) * | 2001-12-10 | 2003-06-25 | Lacent Technologies Inc. | System for cutting patterns preset in a continuous stream of sheet material |
-
1990
- 1990-05-11 CA CA 2016554 patent/CA2016554A1/en not_active Abandoned
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5867392A (en) * | 1993-07-15 | 1999-02-02 | Lectra Systemes | Method for marking or cutting a material along predetermined paths |
| WO1999028798A2 (en) * | 1997-12-02 | 1999-06-10 | Lacent Technologies Inc. | Gantry-mounted laser nozzle and method for controlling laser positioning |
| WO1999028798A3 (en) * | 1997-12-02 | 1999-10-14 | Lacent Technologies Inc | Gantry-mounted laser nozzle and method for controlling laser positioning |
| US6294755B1 (en) | 1997-12-02 | 2001-09-25 | Lacent Technologies, Inc. | Gantry-mounted laser nozzle and method for controlling laser positioning |
| EP1321839A2 (en) * | 2001-12-10 | 2003-06-25 | Lacent Technologies Inc. | System for cutting patterns preset in a continuous stream of sheet material |
| WO2003054646A2 (en) * | 2001-12-10 | 2003-07-03 | Lacent Technologies Inc. | System for cutting shapes preset in a continuous stream of sheet material |
| WO2003054646A3 (en) * | 2001-12-10 | 2004-03-04 | Lacent Technologies Inc | System for cutting shapes preset in a continuous stream of sheet material |
| EP1321839A3 (en) * | 2001-12-10 | 2004-04-28 | Lacent Technologies Inc. | System for cutting patterns preset in a continuous stream of sheet material |
| US7154530B2 (en) | 2001-12-10 | 2006-12-26 | Lacent Technologies Inc. | System for cutting shapes preset in a continuous stream of sheet material |
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